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B Chapuis

Publications and source records attributed to B Chapuis.

113 records · Page 7Linked to original sources
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Transduction of CD34+ cells with lentiviral vectors enables the production of large quantities of transgene-expressing immature and mature dendritic cells.

BACKGROUND: Genetically engineered dendritic cells (DC) presenting specific antigens to T cells may be of great interest for immunotherapy. For this reason, the production of transgene-expressing DC derived from CD34 + cells transduced either shortly after ex vivo purification or during their differentiation into DC were evaluated. METHODS: CD34+ cells were transduced with lentivectors encoding for GFP before or after 21 days of culture with FLT3-ligand, thrombopoietin and stem cell factor and induction into DC with GM-CSF+IL-4 (G4) or G4+TNF (GT4). GFP and DC-specific marker expression was assessed by flow cytometry, and allostimulatory capacity was evaluated on GFP+ and GFP- sorted cells. RESULTS: Immature (G4-induced) DC obtained from amplified CD34 + cells were transducible by lentiviral vectors while mature (GT4-induced) DC were rather refractory. Moreover, since differentiated DC did not proliferate, large quantities of vectors were required to generate transgene-expressing cells with this protocol. In contrast, greater numbers of both immature and mature GFP- expressing DC were obtained with CD34+ cells exposed to lentivector shortly after purification. By the time of DC induction, GFP+ cells had increased by approximately 170-fold. After DC induction with G4, 32% of CD1a+, HLA-DR+, or CD40+ cells expressed GFP. CD1a+E-cadherin+ GFP+ Langerhans-like DC were also obtained. Incubation with TNF induced mature CD83+GFP+ DC that displayed a higher allostimulatory capacity than cells induced with G4 alone. CONCLUSION: The transduction of a small number of CD34+ cells with minimal doses of lentivector may allow for the production of a large number of DC expressing selected antigens useful for immunotherapy.

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PubMedDate not supplied

T-cell repertoire complexity after allogeneic bone marrow transplantation.

We analyzed the T-cell repertoire in patients transplanted with bone marrow from an HLA identical sibling by determining the TCR diversity through Vbeta-CDR3-size spectratyping with Vbeta/Cbeta- and Vbeta/Jbeta-specific primers. Using the Vbeta/Cbeta primers, we observed limited TCR diversity only in recipients of a T-cell-depleted graft, whereas the TCR diversity of patients transplanted with an unmanipulated graft seemed to be indistinguishable from the one of a normal individual. However, with Vbeta/Jbeta-specific primers, increase of the resolution by approximately 10-fold also allowed the detection of imbalances in the TCR repertoire of recipients of an unmanipulated graft. This demonstrates that when high numbers of T cells are cotransfused with marrow, the TCR repertoire is more complete but still not as complete as in normal individuals, thereby emphasizing the important role of coinfused mature T cells in the restoration of the T-cell compartment after bone marrow transplantation.

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